I haven't got a problem - However Im not a fu***ng electrician either. All I know is the cables I use can only go to 40m Max.
The cables / connectors need to be water resistant and fit for purpose etc etc. Three electrically qualified people said the ones I use are the best for that purpose. There was no mention of SY cable of anything else.
Ok we can go and buy specialist cable but I guess a f*****ng jet pack for wfp would be good 2.